JP7586321B2 - Control device, control method and program - Google Patents

Description

The present invention relates to a control device, a control method and a program.

Wireless communication systems such as 5G are being developed that use frequencies with high line-of-sight such as Above-6 GHz. For example, Non-Patent Document 1 shows the results of outdoor experiments at 28 and 39 GHz. FR2 can use a wide band, making it possible to achieve ultra-high-speed communication under good radio wave quality conditions.

5G Outdoor Experiments of Ultra-High Speed, Long Distance Transmission Using Millimeter Waves, Kishiyama, Okumura, et al., DoCoMo Technical Journal (Vol. 26-1, P25-32)

There is a demand for certain devices, such as surveillance cameras that use communication systems to upload high-definition video, to always maintain good communication conditions. However, with conventional technology, wireless signals in the frequency band known as Above-6, such as the 28 GHz band that can be used for 5G and local 5G, tend to travel in a very straight line and suffer significant loss due to obstructions, making it difficult to maintain good communication conditions in an indoor environment with many obstructions and where the obstructions move.

The disclosed technology aims to enable a specific terminal to maintain good communication conditions even in an environment where obstructions are moving.

The disclosed technology is a control device that includes an obstruction detection information acquisition unit that acquires information on detected obstructions, a specific terminal position candidate calculation unit that calculates position candidates for a specific terminal based on the information on detected obstructions , a visibility determination unit that determines whether or not the specific terminal is visible from a base station for each position candidate of the specific terminal , and a base station mobility control parameter calculation unit that determines the position of the specific terminal based on the result of the visibility determination, and calculates mobility control parameters including parameters indicating the position of the base station.

It is possible to maintain good communication conditions for a specific device even in an environment where obstacles are moving.

FIG. 1 is a diagram illustrating an example of a system configuration of a wireless communication system. FIG. 2 is a diagram illustrating an example of a functional configuration of a control device according to the first embodiment. 11 is a flowchart showing an example of the flow of a control process. 11 is a diagram for explaining an example of a method for calculating position candidates of a specific terminal. FIG. FIG. 1 is a first diagram for explaining an example of a method for determining visibility according to the first embodiment. FIG. 2 is a second diagram for explaining an example of a method for determining visibility according to the first embodiment. FIG. 11 is a diagram illustrating an example of a functional configuration of each device according to a second embodiment. FIG. 11 is a diagram for explaining an example of a method for determining visibility according to the second embodiment. FIG. 2 illustrates an example of a hardware configuration of a computer.

Hereinafter, an embodiment of the present invention (the present embodiment) will be described with reference to the drawings. The embodiment described below is merely an example, and the embodiment to which the present invention is applicable is not limited to the following embodiment.

(Outline of the present embodiment)
The wireless communication system of this embodiment determines whether or not each of multiple candidate surveillance camera locations is visible from the base station based on an obstruction map created from information on detected obstructions, and determines a combination of the positions and directions of base stations with visibility and the positions of the surveillance cameras that maximizes the area of the surveillance camera's surveillance area and the quality of the base station's coverage area.

(System configuration example of wireless communication system)
1 is a diagram showing an example of the system configuration of a wireless communication system. The wireless communication system 1 includes a control device 10, a base station 20, an obstacle detector 30, a surveillance camera 40, and a terminal 50. The communication area of the wireless communication system 1 is an area monitored by the surveillance camera 40, and includes an obstacle 60, a wall 70, etc.

The control device 10 is connected to the base station 20 and the obstruction detector 30 so as to be able to communicate with them via wired or wireless communication. The control device 10 acquires information detected by the obstruction detector 30, generates an obstruction map, determines the position and direction of the base station 20, and controls the base station 20.

The base station 20 is a wireless communication base station. The base station 20 is a movable base station that can change its position and direction under the control of the control device 10. The range of motion of the base station 20 may be a sliding one-dimensional range of motion, or a two-dimensional range of motion in which the base station is mounted on a drone, AGV (Automated guided vehicle), etc.

The obstruction detector 30 is a camera or a LiDAR (Light Detection And Ranging) system, etc., and transmits information about the detected obstruction to the control device 10.

The surveillance camera 40 transmits high-definition video of the area being monitored to the base station 20 via wireless communication. The surveillance camera is an example of a specific terminal that should maintain good communication with the base station 20, but it may be something else. For example, the specific terminal may be a repeater for relaying wireless communication.

Terminal 50 is a terminal that uses wireless communication with base station 20.

Below, examples 1 and 2 of this embodiment are described.

(Example of functional configuration of control device according to embodiment 1)
2 is a diagram illustrating an example of a functional configuration of the control device according to Example 1. The control device 10 includes an obstruction detection information acquisition unit 11, an obstruction map generation unit 12, a specific terminal position candidate calculation unit 13, a visibility determination unit 14, and a base station mobility control parameter calculation unit 15.

The obstruction detection information acquisition unit 11 acquires information on the detection of an obstruction by receiving it from the obstruction detector 30.

The obstruction map generator 12 generates an obstruction map showing the position and size of the obstruction in the communication area based on the information of the obstruction detected. The obstruction map may be 3D or 2D. If the obstruction map is 3D, the visibility determiner 14 determines the visibility taking into account the height.

The specific terminal position candidate calculation unit 13 calculates the position candidate of the surveillance camera 40. The position candidate of the surveillance camera 40 is a candidate position where the area to be monitored can be monitored depending on the position and size of the obstruction. A specific example of a method for calculating the position candidate will be described later.

The visibility determination unit 14 determines whether or not the surveillance camera 40 is visible from the base station 20 for each candidate location of the surveillance camera 40. If there are multiple base stations 20, the visibility determination unit 14 determines that there is visibility if there is visibility to any of the base stations 20. Specific examples of methods for determining whether or not there is visibility will be described later.

The base station mobility control parameter calculation unit 15 calculates parameters for mobility control of the base station 20. Specifically, the calculated parameters are parameters indicating the position and direction of the base station 20.

The control device 10 controls the movement of the base station 20 based on the calculated parameters. The base station 20 does not have to be mobile. In that case, the control device 10 outputs information indicating the calculation results. The user simply installs the base station 20 based on the calculation results. When there are multiple base stations 20, these controls may be combined. For example, some of the multiple base stations may be mobile and some may be fixed.

(Example of operation of wireless communication system)
Next, an example of the operation of the wireless communication system 1 will be described with reference to the drawings. When an obstacle is detected by the obstacle detector 30, the control device 10 starts a control process.

3 is a flowchart showing an example of the flow of the control process. The obstruction detection information acquisition unit 11 acquires information on the detection of an obstruction (obstruction detection information) (step S101). Next, the obstruction map generation unit 12 generates an obstruction map based on the obstruction detection information (step S102).

The specific terminal position candidate calculation unit 13 calculates multiple position candidates for the surveillance camera 40 (specific terminal) (step S103). Then, the base station mobility control parameter calculation unit 15 selects a position candidate for the surveillance camera 40 (specific terminal) (step S104).

Next, the base station mobility control parameter calculation unit 15 selects a combination of parameters of the position and direction of the base station (step S105). Specifically, the base station mobility control parameter calculation unit 15 stores in advance information indicating the range of values that can be taken by the parameters of the position and direction of the base station, and selects one from multiple combinations that fall within that range.

Next, the visibility determination unit 14 determines whether or not there is visibility from the base station 20 to the location candidate of the surveillance camera 40 (specific terminal) based on the selected parameters and the location candidate (step S106). If the visibility determination unit 14 determines that there is no visibility (step S106: No), the process returns to step S105, and the base station mobility control parameter calculation unit 15 selects a combination of parameters of the position and direction of the base station 20 that is different from the combination already selected.

If the visibility determination unit 14 determines that there is visibility (step S106: Yes), the base station mobility control parameter calculation unit 15 calculates the monitoring area Ac of the monitoring camera 40 (specific terminal) (step S107). Note that, if the specific terminal is a repeater, the base station mobility control parameter calculation unit 15 may calculate the coverage area of the repeater as Ac.

Next, the base station mobility control parameter calculation unit 15 calculates the coverage area quality Qe of the base station 20 (step S108). The control device 10 stores the calculated Ac and Qe. Then, the control device 10 judges whether or not all of the parameters of the position and direction of the base station 20 have been selected (step S109). If the control device 10 judges that any of the parameters of the position and direction of the base station 20 have not been selected (step S109: No), the process returns to step S105, and the base station mobility control parameter calculation unit 15 selects a combination of the parameters of the position and direction of the base station 20 that is different from the combination already selected.

In addition, when the control device 10 determines that all the position and direction parameters of the base station 20 have been selected (step S109: Yes), it determines whether all the position candidates of the surveillance camera 40 (specific terminal) have been selected (step S110).

If the control device 10 determines that none of the location candidates for the surveillance camera 40 (specific terminal) has been selected (step S110: No), the process returns to step S104, and the base station mobility control parameter calculation unit 15 selects a location candidate different from the location candidate already selected as the location candidate for the surveillance camera 40 (specific terminal).

When the control device 10 determines that all position candidates for the surveillance camera 40 (specific terminal) have been selected (step S110: Yes), the base station mobility control parameter calculation unit 15 selects a combination of the position candidates for the surveillance camera 40 (specific terminal) and the position and direction parameters of the base station 20 that maximize Ac (step S111). Furthermore, the base station mobility control parameter calculation unit 15 selects the position and direction parameters of the base station 20 that maximize Qe from the combinations of the position and direction parameters of the selected base station 20 (step S112).

(Method of calculating position candidates of a specific terminal)
Next, a method for calculating position candidates for the monitoring camera 40 (specific terminal) in step S103 of the control process will be described.

The first calculation method is to determine the elements of the monitored area that can be seen from the position candidates of each surveillance camera 40 (specific terminal) based on an obstruction map. In this method, the specific terminal position candidate calculation unit 13 calculates position candidates so as to maximize the number of elements of the monitored area that are within line of sight (or so that all elements of the monitored area are within line of sight). Here, a distance limit may be set for determining whether or not there is line of sight.

According to the first calculation method, by determining whether or not there is line of sight, it is possible to calculate all candidate positions for the surveillance camera 40 that maximize the number of elements that can be monitored. Furthermore, by considering distance restrictions in the line of sight condition, it is possible to enable more reliable surveillance by taking into account constraints such as camera resolution. Note that, if the specific terminal is a repeater, the number of elements that can be relayed can be used instead of the number of elements that can be monitored.

Figure 4 is a diagram for explaining an example of a method for calculating position candidates of a specific terminal. In a second calculation method, the specific terminal position candidate calculation unit 13 divides the area to be monitored into multiple triangles, such as triangle 101-1 shown in Figure 4.

Then, the specific terminal position candidate calculation unit 13 combines triangles that can be combined (triangles that share two vertices, for example, triangles 101-1 and 101-2, triangles 102-1 and 102-2, and triangles 103-1 and 103-2).

Next, the specific terminal position candidate calculation unit 13 determines the area covered by the joined triangles as a position candidate for placing one surveillance camera 40.

According to the second calculation method, the candidate positions of each surveillance camera 40 (specific terminal) can be calculated using a simpler calculation method.

(Method of determining prospects)
Next, a method for determining visibility in step S106 of the control process will be described.

5 is a first diagram for explaining an example of a visibility determination method according to Example 1. In the first visibility determination method, the visibility determination unit 14 determines that the area within the line of sight is an area 111 through which a line segment 110 passes from the point at the center position of the antenna 21 of the base station 20 to the point where the line segment 110 hits a wall 70 or a shield 60.

According to the first visibility assessment method, the area within visibility can be easily calculated using only the area shape and the position and shape of any obstructions, regardless of the position of the surveillance camera 40 (specific terminal).

Figure 6 is a second diagram for explaining an example of a visibility determination method according to Example 1. In the second visibility determination method, the visibility determination unit 14 calculates a Fresnel zone 121 for each point 120 on a predetermined grid from the point at the center position of the antenna 21 of the base station 20. The visibility determination unit 14 then determines a point in the Fresnel zone 121 where a predetermined X% is not blocked as a line-of-sight position, and determines the surrounding area as a line-of-sight area.

According to the second visibility assessment method, like the first visibility assessment method, the area within line of sight can be easily calculated using only the area shape and the position and shape of obstructions, regardless of the position of the surveillance camera 40 (specific terminal), and it is possible to obtain assessment results that are closer to the actual communication conditions than the first visibility assessment method.

An example of how to calculate the Fresnel zone is as follows: If the shortest distance between the transmitter and receiver is d (m), the radius of the center of the spheroid (Fresnel radius) is r1 (m), the distance from the transmitter to the center of the spheroid is d1 (m), the distance from the receiver to the center of the spheroid is d2 (m), the path difference between the reflected wave reflected at the Fresnel radius and the direct wave is d3 (m), and the wavelength is λ (m), d3 (m) and r1 (m) are calculated using the following formula.

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and

Example 2
A second embodiment will be described below with reference to the drawings. The second embodiment differs from the first embodiment in that the position information of a specific terminal is used to determine visibility and that the specific terminal detects obstructions. Therefore, the following description of the second embodiment will focus on the differences from the first embodiment, and components having the same functional configuration as the first embodiment will be given the same reference numerals as those used in the description of the first embodiment, and the description thereof will be omitted.

(Example of functional configuration of each device according to the second embodiment)
7 is a diagram illustrating an example of a functional configuration of each device according to Example 2. The control device 10 according to this example has a configuration in which a terminal location information acquisition unit 16 is added to the control device 10 according to Example 1.

The terminal location information acquisition unit 16 acquires terminal location information indicating the location of a specific terminal from the base station 20.

The base station 20 comprises a base station moving mechanism 21, a radio transceiver unit 22, and a signal demodulator unit 23. The base station moving mechanism 21 is a mechanism (actuator) that moves the base station under the control of the control device 10.

The wireless transmission/reception unit 22 transmits and receives wireless communication signals to and from the surveillance camera 40 (specific terminal). Specifically, the wireless transmission/reception unit 22 receives terminal position information and obstruction detection information that detects an obstruction from the surveillance camera 40 (specific terminal).

In addition, instead of receiving terminal location information, the base station 20 may estimate the location of the surveillance camera 40 (specific terminal) using camera footage, etc.

The signal demodulation unit 23 demodulates the wireless signal received by the wireless transceiver unit 22. The base station 20 transmits the demodulated signal to the control device 10.

The surveillance camera 40 (specific terminal) comprises a wireless transmitter/receiver unit 41, a location information acquisition unit 42, and an obstruction detection unit 43.

The wireless transceiver 41 transmits and receives wireless communication signals to and from the base station 20. Specifically, the wireless transceiver 41 transmits terminal position information and obstruction detection information to the base station 20.

The location information acquisition unit 42 acquires location information by determining its own location using GPS (Global Positioning System) or sensing, etc.

The obstruction detection unit 43 detects obstructions using a camera or Lidar, etc., and acquires obstruction detection information.

(Method of determining visibility according to Example 2)
Next, a method for determining visibility according to this embodiment will be described.

Figure 8 is a diagram for explaining an example of a visibility determination method according to Example 2. In the visibility determination method according to this example, the visibility determination unit 14 calculates a Fresnel zone 130 for each surveillance camera 40 (specific terminal) from the point of the center position of the antenna 21 of the base station 20. The visibility determination unit 14 then determines that a surveillance camera 40 (specific terminal) for which a predetermined X% of the Fresnel zone 130 is not blocked has visibility.

According to the visibility determination method of this embodiment, when the position of the surveillance camera 40 (specific terminal) is relatively static, it is possible to take into account the area shape, the position and shape of obstructions, and the position of the surveillance camera 40 (specific terminal).

As in the present embodiment, the calculation process of the coverage area quality Qe in step S108 of the control process may take into account the location information of the terminals 50. Specifically, each terminal 50 transmits location information via the base station 20, and the control device 10 receives the location information of each terminal 50.

The base station mobility control parameter calculation unit 15 of the control device 10 determines whether there is line of sight from the base station 20 to each terminal 50 based on the position information of each terminal 50 in calculating the coverage area quality Qe, and calculates the number of elements in the area. This makes it possible to calculate the coverage area quality Qe according to the position of each terminal 50 when each terminal 50 is relatively static.

(Hardware Configuration Example According to the Present Embodiment)
The control device 10 can be realized, for example, by making a computer execute a program in which the processing contents described in this embodiment are described. Note that this "computer" may be a physical machine or a virtual machine on the cloud. When a virtual machine is used, the "hardware" described here is virtual hardware.

The above program can be recorded on a computer-readable recording medium (such as a portable memory) and can be stored or distributed. The above program can also be provided via a network such as the Internet or e-mail.

Figure 9 is a diagram showing an example of the hardware configuration of the computer. The computer in Figure 9 has a drive device 1000, an auxiliary storage device 1002, a memory device 1003, a CPU 1004, an interface device 1005, a display device 1006, an input device 1007, an output device 1008, etc., which are all connected to each other via a bus B.

The program that realizes the processing on the computer is provided by a recording medium 1001, such as a CD-ROM or a memory card. When the recording medium 1001 storing the program is set in the drive device 1000, the program is installed from the recording medium 1001 via the drive device 1000 into the auxiliary storage device 1002. However, the program does not necessarily have to be installed from the recording medium 1001, but may be downloaded from another computer via a network. The auxiliary storage device 1002 stores the installed program as well as necessary files, data, etc.

When a program start instruction is given, the memory device 1003 reads out and stores the program from the auxiliary storage device 1002. The CPU 1004 realizes the functions related to the device according to the program stored in the memory device 1003. The interface device 1005 is used as an interface for connecting to a network. The display device 1006 displays a GUI (Graphical User Interface) or the like according to a program. The input device 1007 is composed of a keyboard and a mouse, buttons, a touch panel, or the like, and is used to input various operation instructions. The output device 1008 outputs the calculation results. The above computer may be equipped with a GPU (Graphics Processing Unit) or a TPU (Tensor processing unit) instead of the CPU 1004, or may be equipped with a GPU or TPU in addition to the CPU 1004. In that case, the processing may be shared and executed, for example, the GPU or TPU executes processing that requires special calculations, and the CPU 1004 executes other processing.

(Effects of this embodiment)
According to the wireless communication system 1 of the present embodiment, the presence or absence of line of sight from each base station to a plurality of position candidates of a specific terminal is determined based on a shielding object map based on information on detected shielding objects, and a combination is determined from the positions and directions of base stations with line of sight and the positions of the specific terminal that maximizes the area of the monitoring area of the specific terminal and the coverage area quality of the base station. This makes it possible to control the positions of specific terminals such as surveillance cameras and repeaters and the positions and directions of base stations in conjunction with each other, and to determine and efficiently locate an appropriate position for the specific terminal while maximizing the coverage area quality.

(Summary of the embodiment)
This specification describes at least the control device, control method, and program described in the following sections.
(Section 1)
A control device for controlling a position and direction of a base station and a position of a specific terminal that wirelessly communicates with the base station in conjunction with each other, comprising:
an obstruction detection information acquisition unit that acquires information on the detection of an obstruction;
a specific terminal position candidate calculation unit that calculates position candidates of the specific terminal based on information of the detection of the obstruction;
a visibility determination unit that determines whether or not the specific terminal is visible from the base station for each of the position candidates of the specific terminal;
and a base station mobility control parameter calculation unit that determines a position of the specific terminal based on a result of the judgment of the presence or absence of visibility, and calculates parameters indicating a position and a direction of the base station.
Control device.
(Section 2)
The specific terminal is a surveillance camera,
the base station mobility control parameter calculation unit calculates a monitoring area of the monitoring camera, and determines a position of the specific terminal so as to maximize the calculated monitoring area;
2. The control device of claim 1.
(Section 3)
the base station mobility control parameter calculation unit calculates a coverage area quality of the base station, and calculates parameters indicating a position and a direction of the base station so as to maximize the calculated coverage area quality;
3. The control device according to claim 1 or 2.
(Section 4)
The visibility determination unit calculates a Fresnel zone from the base station, and determines that a point where a predetermined ratio of an area of the calculated Fresnel zone is not blocked is a visibility point.
4. The control device according to any one of claims 1 to 3.
(Section 5)
A terminal location information acquisition unit that acquires terminal location information indicating the location of the specific terminal,
The visibility determination unit determines whether or not the specific terminal is visible from the base station based on the terminal location information.
5. The control device according to any one of claims 1 to 4.
(Section 6)
controlling the movement of the base station based on the parameters indicating the calculated position and direction of the base station;
6. A control device as claimed in any one of claims 1 to 5.
(Section 7)
A control method executed by a control device for controlling a position and direction of a base station and a position of a specific terminal that wirelessly communicates with the base station in conjunction with each other, comprising:
Control methods.
(Section 8)
A program for causing a computer to function as each unit in the control device according to any one of claims 1 to 6.

Although the present embodiment has been described above, the present invention is not limited to such a specific embodiment, and various modifications and variations are possible within the scope of the gist of the present invention as described in the claims.

1 Wireless communication system 10 Control device 11 Obstruction detection information acquisition unit 12 Obstruction map generation unit 13 Specific terminal position candidate calculation unit 14 Visibility determination unit 15 Base station movement control parameter calculation unit 16 Terminal position information acquisition unit 20 Base station 21 Base station movement mechanism 22 Wireless transmission/reception unit 23 Signal demodulation unit 30 Obstruction detector 40 Surveillance camera 41 Wireless transmission/reception unit 42 Position information acquisition unit 43 Obstruction detection unit 50 Terminal 60 Obstruction 70 Wall 100 Feature point change amount data 1000 Drive device 1001 Recording medium 1002 Auxiliary storage device 1003 Memory device 1004 CPU
1005 Interface device 1006 Display device 1007 Input device 1008 Output device

Claims (8)

an obstruction detection information acquisition unit that acquires information on the detection of an obstruction ;
a specific terminal position candidate calculation unit that calculates a position candidate of the specific terminal based on the information of the detection of the obstruction;
a visibility determination unit that determines whether or not the specific terminal is visible from a base station for each of the position candidates of the specific terminal;
and a base station mobility control parameter calculation unit that determines a position of the specific terminal based on a result of the judgment of the presence or absence of visibility, and calculates mobility control parameters including a parameter indicating a position of the base station.
Control device. The specific terminal is a surveillance camera,
the base station mobility control parameter calculation unit calculates a monitoring area of the monitoring camera, and determines a position of the specific terminal so as to maximize the calculated monitoring area;
The control device according to claim 1 . the base station mobility control parameter calculation unit calculates a coverage area quality of the base station, and calculates the mobility control parameters so as to maximize the calculated coverage area quality;
The control device according to claim 1 or 2. The visibility determination unit calculates a Fresnel zone from the base station, and determines that a point where a predetermined ratio of an area of the calculated Fresnel zone is not blocked is a visibility point.
The control device according to any one of claims 1 to 3. A terminal location information acquisition unit that acquires terminal location information indicating the location of the specific terminal,
The visibility determination unit determines whether or not the specific terminal is visible from the base station based on the terminal location information.
A control device according to any one of claims 1 to 4. controlling the movement of the base station based on the calculated mobility control parameters;
A control device according to any one of claims 1 to 5. The control device,
a shielding object detection information acquisition step of acquiring information on detection of a shielding object;
a specific terminal position candidate calculation step of calculating a position candidate of the specific terminal based on the information of the detection of the obstruction;
a visibility determination step of determining whether or not the specific terminal is visible from a base station for each of the position candidates of the specific terminal;
a base station mobility control parameter calculation step of determining a position of the specific terminal based on the result of the judgment of the presence or absence of visibility, and calculating mobility control parameters including a parameter indicating the position of the base station;
Execute
Control methods. A program for causing a computer to function as each part of a control device according to any one of claims 1 to 6.

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